A $50-cm30-cm20-cm$ block weighing $150$ N is to be moved at a constant velocity of $0\mathrm{.}80\frac{m}{s}$ on an inclined surface with a friction coefficient of $0\mathrm{.}27.($a$)$ Determine the force $F$ that needs to be applied in the horizontal direction. $($b$)$ If a $0\mathrm{.}40-$mm$-$thick oil film with a dynamic viscosity of $0\mathrm{.}012Pa*s$ is applied between the block and inclined surface, determine the percent reduction in the required force.